Presser foot actuating mechanisms for sewing machines



p 13, 1966 o. R. HMS 3,272,161

PRESSER FOOT ACTUATING MECHANISMS FOR SEWING MACHINES Filed Sept. 16,1963 5 Sheets-Sheet 1 Inventor P 13, 1955 o. R. HAAS 3,272,161

PRESSER FOOT ACTUATING MECHANISMS FOR SEWING MACHINES Filed Sept. 16,1963 5 Sheets-Sheet 2 0 Z0 40 60 80 0 I20 I40 16 I50 2.0 E20 2'10 260260 300 320 40 560 mznsuama UPPER at LOWER LOCK Sept. 13, 1966 o. R.HAAS 3,272,161

PRESSER FOOT ACTUATING MECHANISMS FOR SEWING MACHINES Filed Sept. 16,1963 5 Sheets-Sheet 5 Sept. 13, 1966 Filed Sept. 16, 1963 0. R. HAASPRESSER FOOT ACTUATING MECHANISMS FOR SEWING MACHINES E 0 E 240 290 E80b am 340 5 Sheets-Sheet 4 THREAD 0 2o an no :20 mo 1 mznsunme CLOSE IUPPER LOWER LOCK OPEN Sept. 13, 1966 o. R. HAAS 2,

PRESSER FOOT ACTUATING MECHANISMS FOR SEWING MACHINES Filed Sept. 16,1963 5 Sheets-Sheet 5 166 O 164 J66 I United States Patent 3,272,161PRESSIER FOUT ACTUATING MECHANESMS FOR SEWING MACHINES (ltto R. Haas,Wenhani, Mass., assignor to United Shoe Machinery Corporation, Boston,Mass, a corporation of New Jersey Filed Sept. 16, 1963, Ser. No. 3tl9,1811 Claims. (Cl. 112-38) This invention relates to improvements in shoeoutsole stitching machines and more particularly to presser footactuating mechanisms for clamping work in sewing position in suchmachines, examples of which are disclosed in United States LettersPatent No. 1,169,909, granted February 1, 1916, upon application of FredAshworth, No. 1,337,992 granted April 27, 1920, upon application of FredAshworth No. 2,271,611, granted February 3, 1942, upon application ofFred Ashworth and Carl F. Whitaker, and No. 2,148,197, granted February21, 1939, upon application of the present inventor.

In the machines of the patents above referred to the work is clamped atthe operating point of a set of stitch forming devices by a presser footactuated toward and from the work engaging surface of a work support toprevent displacement of the work and to release the work as the work isfed in each stitch forming cycle of machine operation. To accommodatedifferent thicknesses of work ranging from a small fraction of an inchto slightly more than an inch, the presser foot is oscillated toward andfrom the work support by means of a cam actuated lever and adifferential mechanism comprising a floating lever connected to the camlever at one point, to a releasable lock at another point, and to thepresser foot at a third point. The lock acts to release the footmomentarily away from and into re-engagement with the work under theinfluence of a spring, so that it may assume a new clamping position ineach sewing cycle. The initial position assumed when the presser footreengages the work under the influence of the spring determines theamount of pressure exerted in clamping the Work.

One difliculty with a presser foot mechanism acting in this manner isthat a relatively complex lock is required, which is both expensive tomanufacture and critical to control, especially in the presence ofaccumulated dust, oil and other contaminants usually found in areaswhere such machines are utilized. If the presser foot fails initially toengage the work securely or bounces under the influence of the springfrom its position of re-engagement with the work while the lock isbecoming effective, the work may not be clamped properly. Furthermore,other operations, such as thread measurement also are dependent upon theinitial clamping position of the presser foot on the work, so that ifthe clamping action is improper, the amount of thread measured will beincorrect and the accuracy of seam formation may be affected adversely.

The present invention has for an object the provision of a presser footactuating mechanism for an outsole stitching machine, in which there isno need for a complicated lock, so constructed as to be influenced bythe presence of dust or contaminating materials. More specifically,other objects are to provide a presser foot actuating mechanism whichdoes not depend upon the position initially assumed by the presser footas it re-engages the work under the influence of a spring to determinehow much pressure will be exerted in clamping the work or how muchthread is measured for each stitch being formed.

To the ends noted, the invention resides in a shoe outsole stitchingmachine having a frame, stitch forming devices in the frame, a mainsewing shaft for actuating the stitch forming devices, a work support, apresser foot and mechanism driven by the sewing shaft for actuating thepresser foot to clamp and release the work, 'in which machine a presserfoot lever actuated by a cam on the sewing shaft is connected through atrain of adjustable connections between a cam lever and the presser footlever, the adjustment of the connections being accomplished by a lightweight feeler acting independently of the initial position assumed bythe presser foot while re-engaging the work periodically throughout theinsertion of a seam. By the use of a feeler acting independently of thepresser foot the thickness of the work may be calipered continuously bythe feeler to change the adjustment of the presser foot actuatingconnections, so that a more reliable, accurate and sensitive control forthe foot is obtained independently of the mass of the presser foot orits actuating connections.

The invention is equally applicable to any machine whether the machineacts to feed the work for performing an operation on work in astep-by-step manner or continuously without interruption and whether thework is fed by an awl or by joint movements of the work support andpresser foot acting as a clamp, or by both awl and clamp for acontinuous feeding movement of the work. In any type of operationperforming machine, regardless of the nature of work feed employed, thefeeler may engage the work continuously, so that accurate response inthe position of the presser foot is obtained or the feeler may disengagethe Work intermittently for brief intervals in order not to interferewith work feed or to abrade or otherwise injure the surface of the workas the result of relative frictional movement between the work and thefeeler. Even with brief intervals of disengagement a more accuratecalipering action is possible by using an independent feeler than wherean almost instantaneous engagement and locking action is required as apresser foot is finding its own initial position in prior machines.

The use of a feeler movable independently of the presser foot is offurther benefit not only because it avoids the necessity for the presserfoot to find its own initial position on the work under spring actionbefore clamping it but also because the separate calipering action ofthe work requires no more than a relatively light pressure, so that thefeeler may be arranged to adjust reliably the measurement of thread foreach stitch at a time and with a pressure on the work, which is a smallfraction of that needed for the presser foot clamping action. To secureheavy work the presser foot is required to engage and clamp the workwith relatively heavy pressure at critical times in each stitch formingcycle and the work frequently exhibits wide variations incompressability and resiliency, so that thread measurement in priormachines is often affected adversely from this cause.

These and other features of the invention, as hereinafter described andclaimed, will be apparent readily to those skilled in the art from thefollowing detailed description, taken in connection with theaccompanying drawings in which:

FIG. 1 is a view in front elevation of a portion of a shoe outsolestitching machine head embodying the features of the present invention;

FIG. 2 is a detail view in right side elevation of presser footactuating and thread measuring mechanisms, show ing the positions of theparts while operating upon relatively thin work in the machine of FIG.1;

FIG. 3 is a detail plan view of a work calipering feeler for adjustingthe movements of a presser foot showing its relation along the line ofwork feed with a needle and an awl employed in the machine;

FIG. 4 is a detail view in right side elevation and on a somewhatenlarged scale of a portion of a presser foot adjusting cam in themechanisms of FIG. 2;

FIG. 5 is a time chart showing relative movements of the threadmeasuring mechanism including a pair of thread locks employed therein;

FIG. 6 is a right side elevation similar to that of FIG. 2, illustratingthe position of the parts while operating upon relatively thick work;

FIG. 7 is a sectional plan view of a step type awl feed mechanismemployed in the machine, as seen from the line VIIVII of FIG. 6;

FIG. 8 is a view in front elevation of portions of a clamp feed machineutilizing a feeler controlled presser foot;

FIG. 9 is a time chart showing the relationship of thread measuringmechanism and upper and lower thread locks employed therein whenutilizing a clamp feed in the machine, as illustrated in FIG. 8;

FIG. 10 is a modified form of the invention, illustrating in right sideelevation portions of a feeler controlled presser foot mechanism to beutilized in connection with the machine of FIG. 1, in which the feeleris moved away from the work during back feed of a work feeding awl; and

FIG. 11 is a detail sectional view on a somewhat enlarged scale, showinga frictional device employed to stabilize a thread measuring mechanismemployed in the modified form of the invention illustrated in FIG. 10.

Except as hereinafter described, the machine illustrated in the drawingsis generally the same in construction, arrangement of its parts and modeof operation as the machines disclosed in Patent No. 1,169,909 or No.2,271,- 611 above referred to. More specifically, the machine isprovided with a stitching head having a frame 12, in which is mounted apair of main shafts, one being indicated at 14, for actuating lockstitch forming devices including a curved hook needle 16, a curved workfeeding awl 18, a needle looper 20, a thread finger 22, a take-up 24, ashuttle 26, containing a case 28 for a supply of locking thread, and apair of thread locks, commonly identified as front and rear locks 30 and32, between which the needle thread is acted upon by a thread measuringpulloif 34. To measure the proper amount of needle thread for eachstitch in accordance with the thickness of the work being operated uponthe pull-off 34, which is given a stroke during each sewing cycleregulated by a needle thread measuring mechanism, the pull-off actsbetween a pair of fixed thread guides 36 (FIG. 2). From the front lockthe thread is carried upwardly over a guide roll 38 downwardly beneaththe take-up 24 and upwardly to the needle looper 20.

In the machine of the prior Patent No. 1,169,909, the work is clampedduring the formation and completion of each stitch between the workengaging surfaces of a fixed work support 40 and a vertically movablepresser foot 42. The presser foot is secured to the forward end of apresser foot lever 44 actuated by a self-adjusting cam actuatedmechanism, the adjustment of which is accomplished by the initialposition assumed by the presser foot under the yielding action of aspring during a very brief interval of time in each sewing cycle. Duringthe interval of the spring action the presser foot is left free toengage the work, after which the presser foot quickly is locked securelyin position and usually is given an additional squeezing movement tocompress the Work forcibly, thereby clamping it against the worksupport. Since the clamping force of the presser foot on the workfrequently may reach as high as several hundred pounds theself-adjusting action of the presser foot mechanism by initialengagement with the work has always presented a critical problem. Thisis particularly true when it is realized that the self-adjusting actionof the presser foot mechanism not only determines the amount ofadditional work clamping movement imparted to the foot but also controlsthe action of the thread measuring mechanism. If either the presser footmechanism by itself or with the thread measuring mechanism areimproperly adjusted, obviously the formation and tightness of stitchesin a seam will be affected adversely. If there is any tendency for thepresser foot mechanism adjustment to be retarded or for the presser footto bounce as the result of resiliency in the work, irregular stitchesare certain to result or parts of the presser foot mechanism may bestrained unduly and subjected to pressures beyond which they areintended. These conditions are complicated still further by the movementof the presser foot in squeezing the work. Such squeezing movement canbe adjusted manually and may indirectly affect the thread measuringmechanism, so that whenever the squeezing movement is changed the threadmeasuring mechanism also requires readjustment.

In accordance with the present invention the presser foot mechanism isso arranged that it no longer is necessary for it to adjust itself andinstead reliance is placed upon a movable light weight feeler separatefrom the presser foot and arranged to engage the work more or lesscontinuously between the work support and presser while being operatedupon by the stitch-forming devices. By the use of a light weight feelerarranged in this way an instantaneous determination of the workthickness is possible at practically any time during each sewing cycle,so that proper adjustment of other dependent devices are possible fromthe feeler and the mechanisms for actuating the dependent devices, suchas those for measuring thread need no readjustment and no compromise ormodification in the program of timing with relation to the variousstitch-forming functions is necessary.

Under some circumstances it may be desirable to impart to the feelermovement away from the work on the work support, so that the feeler willnot drag along the work frictionally, either in a manner to abrade thework or otherwise to retard the feeding movement. Even with theserestrictions the feeler still is free to find its own position on thework with a relatively light yielding force for a duration of time ineach sewing cycle which is conducive to accuracy in calipering action onthe work. Accordingly, the entire stitch-forming cycle of operations isimproved with better results in a completed seam inserted. Also, thenecessity is avoided for finding a satisfactory presser foot lock, whichwill be secure under all conditions, quick to respond in locking orunlocking the parts, durable in use and inexpensive to manufacture.

The work calipering feeler is indicated at 46 (see FIG. 2) and comprisesa light weight vertical rod slidable freely along a guide in the form ofa block 48 secured to an extension on an arm of a lever 50 (see alsoFIG. 7) comprising a portion of a mechanism for imparting a feedingmovement to the awl, as more fully described in the Ashworth patentreferred to. The feeler 46 is urged yieldingly at all times against theupper surface of a work piece disposed between the work support and thepresser foot, so that it maintains a continuous calipering action on thework, changing its position immediately in accordance with a varyingthickness of the work.

The lower end of the feeler 46 engages the work within the U of aU-shaped lower end on the presser foot 42. In order not to interferewith the operation of the needle 16 and the awl 18 the feeler engagesthe work in advance of their locations, as illustrated in FIG. 3, andthe awl acts to form a perforation for the needle and then moves thework sufficiently to bring the perforation into line with the needlepath. By reason of the block 48 carried by the feed lever 50 the spacingin the direction of work feed between the feeler 46 and the awl 18 iskept constant, so that no possibility of interference exists. In thisway it is possible to transfer an indication given by the feeler 46 tothe presser foot actuating mechanism and to the thread measuringmechanism in accordance with the thickness of the work, adequately inadvance of the time in each sewing cycle when the thread is drawn intothe work to insure use of the measuring thread exactly at the pointwhere the work is calipered. Thus, no delay occurs in deliveringmeasured thread to the stitch-forming devices it and a much moreaccurate thread measurement is possible than heretofore.

The adjustable presser foot actuating mechanism comprises a link 52pivotally connected between the presser foot lever 44 and one of a pairof concentrically pivoted levers 54 and 56. The levers 54 and 56 areloosely fulcrumed concentrically on a shaft 58, the lever 54 beingprovided with a follower 60 engaging a presser foot cam 62 on a sewingshaft 64 and one arm of the lever 56 being pivotally connected to thelink 52.

The levers 54 and 56 comprise mechanism for actuating the presser footto clamp and release the work supported on the work support body andbetween the levers there is a train of adjustable connections arrangedto change the relationship between the levers as the thickness of thework varies between successive stitches. To adjust the connectionsbetween the levers 54 and 56 the work calipering feeler 46 acts directlyon the connections.

The train of adjustable connections between the levers 54 and 56consists of a cam plate 66 rotatably mounted by means of a pin 68 on adownwardly extending arm of the lever 56. The cam plate has an arcuateslot 7!) disposed in eccentric relation to the axis of the pin 68, thearrangement being such that the radius of the slot 70 in a clockwisedirection constantly decreases and in a counterclockwise increases. Theslot 70 is engaged by an arcuate slider 72 pivotally supported on adownwardly extending arm of the lever 54. The changing radius of the camslot 70 is insuflicient to impart movement of the cam plate about itspin 68 when force is applied between the levers 54- and 56. However, thecam plate may be shifted about the pin 68 by a relatively light forceexerted by the feeler 46.

To connect the feeler 46 with the cam plate the upper end of the feelerhas pivoted to it a handle link 74 by a stud 76 fixed in a forwardlyextending arm of a threearrn lever 78 fulcrumed on a screw 80 secured,in turn, to the frame 12 of the machine. To insure that the feeler willengage the work continuously during operation of the machine the forwardarm of the lever 78 is engaged by an upwardly extending yieldable rod 82pressing downwardly on the forwardly extending arm of the lever 78. Toenable the downward pressure on the feeler to be adjusted the rod 82 issurrounded at its upper end by a threaded sleeve 84 having a knurledcollar and the lower end face of the sleeve presses against a resilientspring 86 compressed between the sleeve and a head on the lower end ofthe rod. The sleeve 84 is threaded into an opening in the frame 12 andis secured in adjusted position by means of a check nut 88.

When the feeler 46 is raised it moves the cam plate 66 through theaction of the lever 78 and an arcuate link 90 pivotally connectedbetween the lever 78 and the cam plate. When the feeler is raisedmanually by the handle link 74- it disengages the presser foot also fromthe work. Assuming that the lever 54 remains stationary, as when themachine is brought to rest, upward movement of the feeler causes thearcuate link 96 to move downwardly and the cam plate 66 to move in adirection, in which the slider 72 engages a smaller radius portion ofthe cam slot '70, thus drawing the lower end of the lever 56 toward thelower end of the lever 54-. In so doing the upper end of the lever 56 ismoved toward the right, pulling on the link 52 and raising the presserfoot. If the feeler 46 is lowered a reverse movement of the cam plate 66takes place and the presser foot 44 is brought into engagement with thework, the force of the spring 86 normally being sufficient to producethe work engaging movement of the presser foot. By the spring 86 thefeeler is kept constantly in engagement with the work, so that theposition of the presser foot is always maintained in proper relation tothe work.

The action of the cam follower 60 during rotation of the cam 62 producesa movement of the presser foot toward or away from the work in timedrelation to the movements of the other work engaging and stitch formingdevices in the machine, the lower end of the feeler being slightlyrounded to avoid abrasion or marking of the work. Under normalconditions any movement of the feeler toward or away from the worksupport 40 produces a similar movement in the presser foot, except for aperiodic work clamping and releasing movement imparted to the presserfoot by the cam 62.

When the machine is stopped, upward movement of the handle link 74causes both the feeler 46 and the presser foot 44 to be raised togetherin order to release the work and to enable replacement with a new workpiece. The positions of the parts with the feeler and presser footraised are shown in FIG. 6, while the corresponding positions with thefeeler lowered are shown in FIG. 2.

To insure that the feeler 46 will in no way impede the feeding movementof the work when the work is fed by engagement of the awl 18, the guideblock 48 for the feeler is moved with the work each time it is fed insuch manner that the lower end of the feeler has a slightly greatermovement in the direction of work feed than the work itself. This feedmovement of the feeler is the result of a swinging movement at thedistal end of the lever 50 which is fulcrumed on a shaft 92, shown inFIG. 7. Between the distal and fulcrum ends of the lever 50', it isprovided with a projection which engages one end of a sliding stud 94 onwhich the curved work feeding awl 18 is mounted.

To permit the feeler 46 to move in the direction of work feed the handlelink 74 has a fork across which is fixed a pin 95 and the upper end ofthe feeler 46 is mounted for sliding movement on the pin 95 (FIG. 1). Byreason of the greater work feed movement imparted to the feeler than tothe awl there is no possibility for engagement between the feeler andthe work to retard work feed. During back feeding movement of the awl 18while the work is securely clamped there is no likelihood that anyreverse feeding effort exerted on the work will overcome the grip of thepresser foot and work support. In other respects the work feedingmechanism is the same as disclosed in the Patent No. 1,169,909.

To enable the feeler and the presser foot to be raised from engagementwith the Work automatically an upward-1y extending arm of the lever 78is pivotally connected to a rearwardly extending link 96, the rearwardend of which is similarly connected to an arm on a lever 98 in anauxiliary operation performing mechanism. The auxiliary operationperforming mechanism acts through a link 99 and other connections duringthe final few degrees of rotation of the sewing shaft 64- in the mannerdisclosed in Patent No. 1,337,992 to raise the presser foot and thefeeler together from engagement with the work.

To insure that the amount of thread measured by the measuring mechanismcorresponds to the length required for each stitch in a seam regardlessof the thickness of the work, the pull-off 34 is in the form of anangularly bent arm rotatable about a fixed shaft 100. The pull-off armhas formed in it a slot 1112 engaged by a roll on a pin 1114 mounted ina lower arm of a lever 106 rotatable on a fulcrum stud 107. In its upperarm the lever 106 has an arcuate slot 108, in which is slidably mountedan extending end of a pivot 110. The pivot 110 is secured in one end ofa horizontal link 112, the other end of which is similarly connected at113 to a downwardly extending arm of a vertical lever 114 fulcrumed on ashaft 116 and provided at its upper end with a roll 118 engaging a camslot 120 in a cam 122, the cam being secured to the sewing shaft 64.

When the position of the feeler 4-6 is shifted by changes in thethickness of the work the angle of the plate 66 on its mounting pin 68is made to correspond with the position of the feeler. At the same timethe position of the pin 110 in the slot 108 is shifted through aconnection 8 link 124 pivot-ally connected to the lever 78concentrically with the link 90. Thus, the effective length of the upperarm of lever 106 is changed and the amount of movement imparted to thepull-off arm 34 by the cam 122 is increased or decreased in accordancewith the thickness of the work.

The advantage of a continuous calipering action by the feeler on thework for the purpose of adjusting the thread measuring mechanism isillustrated in FIG. 5. In this figure the upper curve labeled THREADMEASURING indicates that it is relatively easy to provide a slow uniformmovement in the pull-off arm 34 between 20 and 320 of rotation in themain sewing shaft 64 and a. maximum time period of 300 may be utilizedin actuating the pull-off arm. During this period the upper lock 30 isclosed and the lower lock 32 (FIG. 2) is held open, so that a reliablethread measuring action may take place without any sudden impulse beingimparted to the thread. The timing is illustrated by the curves labeledUPPER AND LOWER LOCKS. Accordingly, a much more uniform thread measuringaction can be accomplished than where the thread must be measured in abriefer interval. The only time in which the upper thread lock 30 needsto be held open is during the last 20 of rotation in the sewing shaft 64while each stitch is being set by tensioning the thread with the take-up24.

The relative positions of the needle 16, awl 18 and feeler 46 along theline of a seam, as best shown in FIG. 3, the work being fed from rightto left. From this figure it is apparent that the feeler 46 engages thework approximately a stitch length in a advance of the point ofoperation of the needle and awl, as the work moves in the direction offeed, indicated by the arrow 125. The feeler is thus able to caliper thework before the effective thickness is modified by the penetratingaction of either the needle or awl. Also, during each sewing cycle, inthe illustrated machine, the feeler engages the work in advance of theneedle and awl, regardless of the type or shape of presser footemployed. For this reason the thread measuring mechanism is capable ofbeing adjusted in ample time to furnish a length of measured thread fora stitch inserted at the same location at which the work was caliperedrather than at a position one or more stitches beyond the caliperinglocation, as occurs in prior machines in which the presser foot mustperform its own work oalipering action. The use of the present presserfoot mechanism with a work calipering feeler is of advantage not only inthe operation of a sewing machine having a work feeding awl but is alsoof benefit in a machine, in which the work is fed by a clamp, as in themachine illustrated in Patent No. 2,271,611, above referred to.

An application of a feeler adjusted presser foot and thread measuringmechanisms to a clamp feed machine is illustrated in FIGS. 8 and 9. Inthe case of a clamp feed machine the work calipering feeler ismaintained in a fixed position along the line of a seam and the work isfed while it is being gripped in the clamp, comprising a work support126 and a presser foot 128, both of which are mounted in a carrier 129for moving them while clamping the work. In a clamp feed machine theneedle indicated at 130, and the awl at 132, are mounted for oscillatingmovement in a common fixed path toward and from the work and no feedingmovement need be imparted to either one. The feeler, indicated at 134 inthis machine, is positioned close to the common path of the needle andawl and is slidable for movement toward and from the work within a guide136 fixed to the frame of the machine. At its upper end the feeler 134is pivotally connected to a handle link 138, which, in turn, issimilarly connected to a fork on the forward end of a three-armed lever140, corresponding to the lever 78 shown in FIGS. 1 and 2. In this casethe lever 140 is acted upon by a spring pressed rod 142 similar inconstruction to the rod 82in FIGS. 1 and 2.

With the use of the calipering feeler 134 in a clamp feed machine, inwhich it is guided in fixed relation to the needle and awl, advantagessimilar to those in an awl feed machine are obtained. By reference toFIG. 9, it is evident that a thread measuring movement of the pull-offarm, as illustrated in the uppermost curve labeled THREAD MEASURING, maytake place during a full 300 time period of rotation for the main sewingshaft. The upper and lower thread locks 30 and 32 are actuated duringthe times indicated by the curves UPPER AND LOWER LOCKS. An addedadvantage in the use of a clamp feed machine results in maintaining thelength of feed more uniformly than with an awl feed machine, therigidity of the work support and presser foot being greater than that ofan awl. In this way closer conformity with the requirements is possiblebecause where the feed is nonuniform, variations in thread requirementsare bound to occur.

In the operation of the work calipering feeler in either an awl or clampfeed machine, as thus far described, the feeler is in continuousengagement with the work during operation of the machine. In order toavoid retarding the feed of the work by reason of frictional engagementwith the feeler it may be desirable to disengage the feeler from thework during feeding movement of the awl in an awl feed machine or duringback feeding movement of the clamp in a clamp feed machine. To theseends the machine of FIGS. 10 and 11 provides mechanism for actuating thework calipering feeler in this way. The disengagement of the work by thefeeler in a machine having a feed of either type should occur while thepresser foot releases its grip on the work. Thus, the time ofdisengagement of the work calipering feeler would be the same in the twotypes of machine.

Referring more particularly to FIGS. 10 and 11, the machine illustratedis of the awl feed type, as shown in FIGS. 1 to 7, inclusive, while thegeneral arrangement of the operating parts in the presser foot andthread measuring mechanisms are also the same. The principal differencebetween the machine of FIGS. 1 to 7, inclusive, and that of FIGS. 10 and11 is in the arrangement of the cam plate forming the train ofadjustable connections between the two concentrically mounted actuatinglevers 54 and 56. In the machine of FIGS. 10 and 11 these presser footconnections have been changed in their general arrangement.

As shown in FIG. 10, the machine is provided with a presser foot lever144 pivotally mounted on a shaft 146 in a fixed portion of a machineframe 148. To urge the presser foot into engagement with a work piececarried by the work support a downwardly extending arm of the lever 144is connected with one end of a resilient tension spring 150, the otherend of which is attached to a pin 152 on the machine frame 148. Thespring not only causes the presser foot to move downwardly intoengagement with the work but also causes the feeler to be pressedyieldingly against the work through reaction on the train of adjustableconnections.

The work calipering feeler in the machine of FIGS. 10 and 11 isindicated at 154 and is similar in construction to that of the machinesin FIGS. 1 to 9, inclusive. The feeler 154 consists of a vertical rodslidingly mounted in a guide block 156 secured to the distal end of afeed lever 158, similar to that indicated at 50 in FIG. 7, the leverintermediate its ends having a projection to actuate an awl supportingstud 160. The work support is indicated at 162 and is secured to themachine frame.

The work calipering feeler 154 is pivotally connected at its upper endto a handle link 164, which, in turn, is pivotally connected to athree-armed lever 166 fulcrumed at 168 on the machine frame 148. Arearwardly extending arm of the lever166 is connected through a link 170to a pivot 172 on a cam plate 174, having a generally horizontal arcuateslot 176 within which is loosely guided a slider pin 178. To provideadjustable presser foot connections the slider pin 178 is secured to onearm of a lever 180 fulcrumed on a shaft 182 concentrically fulcrumedwith a second lever 183, a forwardly projecting arm of which carries apivot 184, the cam plate 174 being rotatably mounted on the pivot 184. Arearwardly extending arm of the lever 183 supports a cam roll 186engaged by a cam on a sewing shaft 188, similar to that in the machinesof FIGS. 1 to 9, inclusive. As in the machines described the connectionsbetween the work calipering feeler 154 and the presser foot lever 144through the cam plate 174 cause the feeler and presser foot to movetogether, except when the lever 183 is actuated by the cam on the sewingshaft.

By reason of the arrangement of the cam slot 176 in the plate 174 atapproximately a horizontal position rather than a vertical one, movementof the cam plate in a vertical direction causes the feeler 154 also tomove vertically rather than to remain stationary, as in the previouslydescribed machines. The action of the spring 150 through the connectionsbetween the presser foot and the feeler exerts a relatively light forceon the feeler, so that the spring causes the presser foot to engage thework with a heavy pressure, whereas the previously described feeler mayengage the work with a heavier pressure.

The action of the lever 183 in raising the presser foot from engagementwith the work causes the feeler 154 to be pressed against the work andthen to impress a swinging movement on the cam plate 174 about itsmounting pivot 184, thus changing the adjustment of the mechanism. Ifthe thickness of the work remains the same from one stitch to another nomovement of the cam plate about its mounting pin 184 occurs.

The cam for actuating the roll 186 on the lever 183 is so shaped that itcauses the feeler to disengage the presser foot from the work, so thatthe work may be fed by the awl without retarding the work by engagementwith the feeler. The feeler is moved into engagement with the work justbefore the presser foot, so that it may caliper the thickness of thework before it is compressed by the presser foot. Thus, the feeler isgiven -at least one complete reciprocation toward and from the workduring each sewing cycle.

In order to adjust the measurement of thread in accordance with thethickness of the work in the machine of FIGS. 10 and 11, the feeler actsthrough the link 170 and a bar 190 pivotally supported on the pivot 172and having a lower end of reduced diameter sliding within a bore formedin a guide rod 192 with a telescoping engagement. The lower end of therod 192 is pivotally connected by a pin 194 to the forward end of a link200 actuated by a cam lever 20 2 through a pivotal connection 204. Thepin 194 connecting the links 192 and 200 is slidingly mounted in anarcuate slot 206 in a lever 208. The lever 208 is fulcrumed on a fixedshaft 210 and has secured in a downwardly extending arm a pin 212. Aroll on the pin 212 is slidingly engaged in a vertical slot formed in apull-off arm 214, which is rotatable on a shaft 216 secured in themachine frame. The pulloff arm 214 acts on the thread between two guideeyes 218 in the manner explained in the above-described machines andpull-off action is adjusted by connections including the bars 190 and192.

The bars 190 and 192 are connected together through a limited lostmotion joint by reason of their telescoping engagement. To limit thelost motion between the bars the reduced end of the bar 190 carries across pin 22!) extending through slots 222 at opposite sides of the bar192. The length of the solts 222 is suificient to enable the feeler 154to be reciprocated freely toward and from the work without actuating thebar 192 so long as the feeler always re-engages the work in the sameposition. When the position of the feeler is changed from one stitch toanother by reason of a variation in the thickness of the work the crosspin 220 is pressed by one end of 10 the slot 222 and moves the bar 192to adjust the thread measuring movement of the pull-off 214.

To retain the bar 192 in its adjusted position when no movement isimparted to it, it is surrounded 'by a friction guide consisting of apair of semicylindrical fiber pieces 224 (see FIG. 11). The fiber pieces224 are supported in a pair of grooves, one of which is formed within asupport block 226 having a cylindrical projection and the other of whichis formed within a cap plate 228 secured yieldingly in co-operativerelation with the block 226, in order to impart friction to the bar 192.

To enable the friction on the bar 192 to be regulated the block and thecap plate are perforated to receive a bolt 230, around which is coiled aspring 232 compressed between the cap plate 228 and a thumb nut 234threaded on the bolt 230. During operation of the machine as the lever208 swings about the shaft 210 the friction device, comprising the block226 and the cap plate 228, may move horizontally to some extent toaccommodate the swinging movement of the lever 208. To enable freehorizontal movement the cylindrical projection of the block 226 isslidingly mounted within a passageway 236 in the machine frame 148.

Although the feelers 46 and 154 are shown in the drawings as beingarranged to engage the work operated upon directly in line with a seaminserted it may be advantageous under some conditions to arrange thefeelers at a location out of line with the seam. Location of the feelerout of line with the seam may be desirable when the In chine is operatedto sew outsoles or other heavy materials.

While the use of a feeler separate from a presser foot in a heavilyconstructed shoe outsole stitching machine is of benefit in adjustingboth the clamping action of the presser foot and the pull-off action ina thread measuring mechanism, when the adjusting connections are ofmechanical construction a separate feeler also is of marked advantagewhen a hydraulically operated presser foot is employed. In the latterinstance the feeler is connected to a servo valve for adjusting theopera tion of the presser foot while the presser foot clamping andreleasing movement may be accomplished by a simple piston and cylinderarrangement actuated by a cam on the main sewing shaft of the machine.Such hydraulic adjustment and actuation are of further benefit inavoiding lost motion normally occurring in mechanical mechanism andconnections. A hydraulic system, thus, is enabled to reach higher speedsof machine operation without sacrificing accuracy of adjustment. Infact, in many instances a hydraulic adjusting system for the presserfoot can be operated more uniformly and with less wear and abuse of themoving parts than is possible with a purely mechanical presser footadjusting and actuating mechanism.

The present invention has been described as being applied to an outsolestitcher, but the features of invention relating to a feeler controlledpresser foot may also be utilized effectively in a stitch separatingmachine of the type disclosed in United States Letters Patent No.1,357,- 511, granted November 2, 1915 on application of Perry. Insteadof stitch forming devices of an outsole stitcher, that machine isprovided with operating devices including an indenting tool. In otherrespects a presser foot and a work support are utilized in that machinefor purposes similar to those of the present sewing machine. Thus, thepresent invention is intended for use with machines for performingoperations other than sewing, except for those features relating tothread measurement. With such use the terms operation performing andstitch forming are equivalents.

The nature and scope of the invention having been indicated and severalembodiments having been described, what is claimed is:

1. A sewing machine having a frame, stitch forming devices in the frame,a main sewing shaft for actuating the stitch forming devices, a worksupport, a presser foot and mechanism for actuating the presser foot toclamp and release the work supported on the work support, including apresser foot lever, a presser foot cam on the sewing shaft, a followerengaging the presser foot cam, and a train of adjustable connectionsbetween the follower and the presser foot lever, in combination with afeeler arranged to engage the work between the work support and thepresser foot for changing the adjustment of the connections between thefollower and the presser foot levers as the thickness of the work variesbetween successive stitches.

2. A sewing machine, as in claim 1, in which there is provided resilientmeans connected with the feeler for pressing it against the work.

3. A sewing machine, as in claim 1, in which the adjustable connectionsinclude a first lever on which the cam follower is mounted, a platehaving an arcuate slot, a second lever fulcrumed concentrically with thefirst lever, the plate being rotatably supported by one of theconcentrically pivoted levers, a slider on the other concentricallypivoted lever, said slider engaging the slot in the plate and the feelerbeing connected to rotate the plate on the lever by which it issupported.

4. A sewing machine, as in claim 1, in which there is provided means forfeeding the work comprising mechanism for moving the awl while engagingthe work and a guide block for the feeler connected to the feedingmechanism to cause the feeler to partake of the work feeding movements.

5. A sewing machine, as in claim 1, in which there is provided means forfeeding the work comprising a carrier for moving the work support andpresser foot while clamping the work, and a guide mounted on the frameof the machine to prevent the feeler from moving with the work as thework is being fed.

6. A sewing machine, as in claim 1, in which there is provided resilientmeans connected with the presser foot acting to press the presser footand the feeler against the work.

7. A sewing machine, as in claim 6, in which the presser foot mechanismactuates both the feeler toward and from the work to prevent the feelerfrom engaging the work frictionally.

8. A sewing machine, as in claim 3, in which the slotted plate is sosupported on its pivoted lever that movement toward and from the worksupport is imparted to the feeler to prevent the feeler from engagingthe work frictionally.

9. A sewing machine, as in claim 8, in which there are providedadjustable thread measuring mechanism and a lost motion joint betweenthe feeler and the thread measuring mechanism to cause adjustment of thethread measuring mechanism when a change in the thickness of the workoccurs and means for retaining the adjustment of the thread measuringmechanism during the relative movement of the parts in the lost motionjoint.

10. A sewing machine having a frame, stitch forming devices in theframe, a main sewing shaft for actuating the stitch forming devices, awork support, a presser foot and mechanism for actuating the presserfoot to clamp and release the work on the work support including apresser foot cam on the sewing shaft and a train of adjustableconnections between the cam and the presser foot lever, in combinationwith a feeler arranged to engage the work between the work support andpresser foot for changing the adjustment of the connections as thethickness of the work varies between successive stitches.

11. A sewing machine, as in claim 10, in which there is providedresilient means connected directly to the presser foot lever forpressing the feeler against the work through reaction on the adjustableconnection.

References Cited by the Examiner UNITED STATES PATENTS 1,169,909 2/1916Ashworth 112-38 2,271,611 2/1942 Ashworth et a1. 11238 2,750,908 6/1956Odermann et a]. 112-235 FRANK I. COHEN, Primary Examiner.

P. D. LAWSON, Assistant Examiner.

1. A SEWING MACHINE HAVING A FRAME, STITCH FORMING DEVICES IN THE FRAME,A MAIN SEWING SHAFT FOR ACTUATING THE STITCH FORMING DEVICES, A WORKSUPPORT, A PRESSER FOOT AND MECHANISM FOR ACTUATING THE PRESSER FOOT TOCLAMP AND RELEASE THE WORK SUPPORTED ON THE WORK SUPPORT, INCLUDING APRESSER FOOT LEVER, A PRESSER FOOT CAM ON THE SEWING SHAFT, A FOLLOWERENGAGING THE PRESSER FOOT CAM, AND A TRAIN OF ADJUSTABLE CONNECTIONSBETWEEN THE FOLLOWER AND THE PRESSER FOOT LEVER, IN COMBINATION WITH AFEELER ARRANGED TO ENGAGE THE WORK BETWEEN THE WORK SUPPORT AND THEPRESSER FOOT FOR CHANGING THE ADJUSTMENT OF THE CONNECTIONS BETWEEN THEFOLLOWER AND THE PRESSER FOOT LEVERS AS THE THICKNESS OF THE WORK VARIESBETWEEN SUCCESSIVE STITCHES.